How's this ?

A transaction moves value from one or more previous outputs, to one or more new outputs.

Note : there is a small, but important difference between outputs, and UTXO's, the former referring to *both spent and unspent outputs, the latter (Unspent Transaction Outputs) referring only to unspent outputs, thus the actual value available for transferring.

During this process there is made use of inputs, whose role it is to specify which of the previous outputs are to be spent on the new outputs, as well as authorizing the transaction through the use of the owner’s digital signature, thereby providing proof-of-ownership.

Each output also gets signed with the input’s specific script signature, thus ensuring that the output can’t be changed after authorization by the owner.

In short ; During a transaction, one or more outputs get moved from a previous transaction onto a new address, creating one or more new outputs.

Inputs act as a bridge to facilitate the transfer of one or more previous outputs, to one or more new outputs, while specifying which of the previous outputs are to be spent on the new outputs, providing proof-of-ownership through use of the owner’s digital signature and signing the output independently through the use of the input’s specific script signature, thus ensuring the the outputs can’t be changed afterwards.

Following is an example of a common transaction ;

A common transaction oftentimes includes some change, which gets returned to the owner.

Example ;

Alice wants to buy a cup of coffee, which costs $ 1.50.

She only has a five-dollar bill with her, which she uses to pay for the cup of coffee.

She receives her cup of coffee, along with the change from the five-dollar bill, amounting to $ 3.50.

The next day, Alice decides to buy another cup of coffee, this time paying with bitcoin.

She orders her cup of coffee as usual, but this time she asks to pay using bitcoin.

Once the order has been typed into the register, it displays the due amount as follows :

Total:

 $1.50 USD 0.015 BTC 

The Point-of-Sale system automatically creates a payment request QR code, which is an encoded URL that contains a destination address, a payment amount, and a generic description such as "Bob’s Cafe."

The payment request QR code encodes the following URL :

bitcoin:1GdK9UzpHBzqzX2A9JFP3Di4weBwqgmoQA?

amount=0.015&

label=Bob%27s%20Cafe&

message=Purchase%20at%20Bob%27s%20Cafe

Components of the URL

A Bitcoin address: "1GdK9UzpHBzqzX2A9JFP3Di4weBwqgmoQA"

The payment amount: "0.015"

A label for the recipient address: "Bob's Cafe"

A description for the payment: "Purchase at Bob's Cafe"

She opens up her wallet-app on her smartphone, scans the QR code and the payment gets sent.

tying back to the picture above about a common payment ; Alice’s wallet holds one address, containing one UTXO ( Unspent Transaction Output ) with a value of 0.05 BTC.

She scans the QR code and pays for the cup of coffee, thus creating an input that specifies which output gets spent, as well as signing it through the use of her digital signature and the input’s specific script signature.

Since Alice’s UTXO has a higher value then what is needed ( 0.05 against 0.015 ), the input creates two new outputs, one for Bob’s address, and one containing the change of the transaction, in this case being 0.035 BTC.

*Note : Fees can be applied, causing the change-output to be lower. The above example shows a transaction without transaction fees.

If we take the example above, and add transaction fees, it would only result in a lower change-output, since the fees would be deducted.

With exemplary fees of 0.0005 BTC, that creates a change-output of 0.0345 BTC.

*It doesn't show the picture here, but if you Google "Common bitcoin payment input output" you'll get an idea of the picture.

Please tell me if the above is correct !